The internal stream state sets the timeout to 120 seconds 2 seconds
after the creation of the flow, attach this internal stream state to the
IPS_ASSURED flag for consistent event reporting.
Before this patch:
[NEW] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 [UNREPLIED] src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282
[UPDATE] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282
[UPDATE] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [ASSURED]
[DESTROY] udp 17 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [ASSURED]
Note IPS_ASSURED for the flow not yet in the internal stream state.
after this update:
[NEW] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 [UNREPLIED] src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282
[UPDATE] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282
[UPDATE] udp 17 120 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [ASSURED]
[DESTROY] udp 17 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [ASSURED]
Before this patch, short-lived UDP flows never entered IPS_ASSURED, so
they were already candidate flow to be deleted by early_drop under
stress.
Before this patch, IPS_ASSURED is set on regardless the internal stream
state, attach this internal stream state to IPS_ASSURED.
packet #1 (original direction) enters NEW state
packet #2 (reply direction) enters ESTABLISHED state, sets on IPS_SEEN_REPLY
paclet #3 (any direction) sets on IPS_ASSURED (if 2 seconds since the
creation has passed by).
Reported-by: Maciej Żenczykowski <zenczykowski@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nf_conntrack_proto_udp.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c
index f8e3c0d2602f..3b516cffc779 100644
--- a/net/netfilter/nf_conntrack_proto_udp.c
+++ b/net/netfilter/nf_conntrack_proto_udp.c
@@ -104,10 +104,13 @@ int nf_conntrack_udp_packet(struct nf_conn *ct,
*/
if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
unsigned long extra = timeouts[UDP_CT_UNREPLIED];
+ bool stream = false;
/* Still active after two seconds? Extend timeout. */
- if (time_after(jiffies, ct->proto.udp.stream_ts))
+ if (time_after(jiffies, ct->proto.udp.stream_ts)) {
extra = timeouts[UDP_CT_REPLIED];
+ stream = true;
+ }
nf_ct_refresh_acct(ct, ctinfo, skb, extra);
@@ -116,7 +119,7 @@ int nf_conntrack_udp_packet(struct nf_conn *ct,
return NF_ACCEPT;
/* Also, more likely to be important, and not a probe */
- if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
+ if (stream && !test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
nf_conntrack_event_cache(IPCT_ASSURED, ct);
} else {
nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[UDP_CT_UNREPLIED]);
--
2.30.2
